They are about $64USD + shipping. They install easy just like a screwing in a light bulb. 10 seconds. It will take you longer to remove the overrun clutch part from the shipping box vs. installing one. The good thing other than the safety is the fact that the PTO access works even better since the connection to the implements is now 8-inches farther out from the tractor, but still in the PTO shielded area.
Oh, OK, I thought it was going to be in the clutch assembly its self, inside. I will order one.
Thanks RUMBLON
